This invention relates generally to a method and an apparatus for chipping large plastic items such as piping, conduit, etc.
In recycling polymeric articles such as polyethylene pipe, or other products made of polyethylene, polypropylene, nylon, polybutylene, etc., the products, once reduced to chips of manageable size, are fed into a granulator machine for grinding and subsequent reuse in molding processes, to produce new articles. A problem arises in how to reduce large polymeric articles, such as polyethylene pipe, which may be several feet in diameter, into pieces or chips small enough to be handled by the granulator machine.
The conventional method involves cutting the pipe with a band saw into manageable sections which can then be split into chips or pieces small enough to be used by the granulator. This is a labor-intensive and time-consuming process.
Devices for chipping wood products are known. For example, U.S. Pat. No. 3,856,212, issued to Swatko, discloses a wood chipper having a disc with blade portions angled towards a shaft and openings for discharging the chips through the disc. U.S. Pat. No. 3,635,410, issued to Smith, discloses a wood chipper having an intake chute at an angle with respect to a wood chipper disc.
U.S. Pat. Nos. 5,020,759 and 3,844,489, both issued to Strong, discloses rollers for supporting logs being fit into a wood chipping machine.
The foregoing known wood chipping devices, however, are not designed for chipping large plastic articles, such as polymeric, and in particular polyethylene pipe, and according, there exists a need for such a device.
It is, therefore, the principal object of this invention to provide a device for chipping polymeric articles.
Another object of the present invention is to provide a device for chipping polymeric pipe.
Yet another object of the present invention is to provide an improved chipping device which can be used to chip polymeric or wood articles.
Still another object of the present invention is to provide a method for chipping polymeric articles.
Generally, the present invention includes a chipper having an intake chute for receiving articles, and in particular polymeric pipe, the intake chute including a live roller conveyer for supporting the pipe as it is drawn into the chute. A rotating chipper disc, or blade, is provided which is driven by a diesel or gas engine, electric motor, hydraulic motor, or the like. The intake chute is disposed at an angle with respect to the chipper blade such that during operation, once the chipper blade engages the polymeric article or pipe to be chipped, such pipe or articles are pulled into the machine by the blade automatically due to the angle at which the intake chute is disposed with respect to the chipper blade. This angle may be approximately 30xc2x0. Thus, by having the pipe or other article approach the chipper blade at that angle, the pipe or other article is continually drawn into the chipper by rotation of the chipper blade.
Another feature of the present invention is the provision of a discharge chute designed for discharge of polymeric chips. The discharge chute is attached to the housing of the chipper device adjacent the chipper blade such that as plastic pipe and articles which pass through openings in the chipper blade, and which are sheared there through interaction of the opening and one or more bed knives provided in the chipper device, the chips thus created are propelled away from the chipper blade by a series of paddles carried on the backside of the chipper blade. These paddles kick the plastic chips upwardly, tangentially with respect to the chipper blade, and to the discharge chute.
The chute is designed to guide and constrain what in essence is projectile motion of the chips, meaning that the chips follow an arcuate path which is first directed upwardly, but which then curves downwardly towards the opening of the chute. This configuration of the discharge chute allows for increased throughput of plastic chips, as would be compared to a discharge chute ordinarily found in a wood chipper.
The present invention also includes a chipper disc which has modified paddles as compared to those used on a conventional wood chipping devices. The chipper disc has been modified to include paddle extensions which cause the paddles to taper inwardly towards the shaft on which the chipper blade rotates. These tapered-in portions of the paddles reduce the likelihood of one or more chips becoming jammed adjacent the backside of the chipper blade.